46. The most appropriate way of mitigating the problem of interference between power line

and communication line is to

(^) Transpose the power line (8) Transpose the communication line
(C) Use double circuit power line (D) വടം bundled conductor power line
47. What will be the nature of fault if a power system is subjected to a fault which makes the
zero sequence component of actual current equal to zero ?
(^) LG fault (8) 11 fault
(¢) ۲۱06 fault (2) ۲٢ fault
48. Which of the following stability is increased with the use of high speed circuit breakers
in power system ?
(൧) Frequency stability (B) Steady state stability
(C) Transient stability (D) ‏11ھ‎ of the above
49. ൧ transmission line has 4 units of string insulators. The voltage across the bottom most
unit is 45% of the total voltage, then the string efficiency of the arrangement is
(A) 33.33% (B) 25%
(C) 66.67% (D) 55.55%
50. A single phase two conductor line separated at a distance 1.5 m apart with radius of 2 cm
each, produce a self-inductance of
(^) 1.83 mH/kM )8( 41
(ಲ) 2.81 4 (D) 0.828 mH/kM
51. Class A commutation 15 also called
(^) Self commutation (B) Resonant pulse commutation
(C) Complementary commutation மு) 1406 commutation.
52. The advantages of using freewheeling diode are
(A) Input power factor is improved (18) Load current waveform is improved
(C) Better load performance (D) All of the above
53. A step up chopper has an input voltage of 200 ۷۰ The conduction time of the thyristor is
300 us and the output voltage is 600 V. If the pulse width is halved for constant
frequency operation, the new output voltage is
(A) 450 9 (B) 400V
(C) 300 9 (D) 500%
54. Three SCRs are connected to form a series string. The voltage across these thyristors are

300 V, 250 V and 200 V respectively. If the current flowing through these thyristors are
5 A, 9 A and 11 A respectively, what will be the value of equalising resistance to be
connected across each SCR’s ?

(A) 10೧
(൭ 152
ങ്‌

(0) 12೧

(B) 132